It is well known in the field of macro photography that when using flash lighting, standard on-camera and built-in flash units are not suitable. Typically, these flash units are located distant from the lens, and in fact are intentionally displaced in order to reduce “red eye”. Likewise, the flash has a parallax with respect to the lens, resulting in a distinct shadowing for objects close to the lens. Finally, due to the uneven illumination, automatic exposure algorithms may fail.
In a macro photographic environment, the lens of the camera is usually very close to the subject, and depending on the desired magnification, may be from less than one inch up to a distance of 24 inches. Typical macro flash units used include ring light flash units that attach to the front of the camera lens, and single or twin flashes mounted off the camera and connected to the camera via an electronic cord or an IR communication port. Two (or more) point sources of light are much preferred in macro photography because at close working distances associated with macro photography a single point source causes contrasting shadows.
U.S. Pat. No. 6,402,358 (Larimer), expressly incorporated herein by reference, discloses a flash system which employs fiber optic illumination to allow precise control and positioning of a light source, suitable for macro photography. See: U.S. Pat. No. 4,006,487 (Allen); U.S. Pat. No. 4,065,859 (Mecklenborg); U.S. Pat. No. 4,428,029 (Baliozian); U.S. Pat. No. 4,464,705 (Horowitz); U.S. Pat. No. 4,519,684 (Francis, Jr. et al); (U.S. Pat. No. 4,575,208 (King); U.S. Pat. No. 5,029,309 (Jones); U.S. Pat. No. 5,034,761 (Jones); and U.S. Pat. No. 5,860,850 (Larimer), each of which is expressly incorporated herein by reference.
See also:
Gilman, “Photo Slit Lamp Biomicrography”;
webeye.ophth.uiowa.edu/ops/op-photo/slitlamp/slitlamp.htm.
“Fiber Optic Illuminator Research Project”; eetd.161.gov/btp/fiberoptics.html.
“Fiber Optic Illuminator;” www.wpiine.com/wpi/microscopycameras/fo illuminator.html.
“Long-Life Fiber Optic Illuminator”.
“Fiber Optic Lighting Systems: An Overview”; www.fiberstars.com/overview.html.
“Fiber Optic Systems”; eande.lbl.gov/R-LabDG/help3503.htm.
“Fostecfiber Optic Bundles with Halogen Light”; www.subtechnique.com.
“Fiber Optic flux Calculation”; eande.lbl.gov/R-Lab DG/Help 3503.htm.
“NAVITAR CCTV Lens Accessories and Fiber Optic Lighting”;
www/subtechnique.com/noframes/navitar/oem/vlacc.htm.
“140 Most Advanced Fiber Optic Illuminators”;
www.kentscientific.com/99WebCatalog/140.html.
“Fiber Optic Bundles”; www.perkinelmer.com/opto.111.
In order for a modern film or digital camera to utilize its through-the-lens light metering system (TTL) it must communicate electronically to the flash unit. This means that each camera manufacturer has dedicated flash units that will operate on specific cameras. Not all manufacturers that produce standard flash units for their cameras also make special macro flash units, although some alternate suppliers may provide TTL compatible flash units. The less advanced consumer cameras often have only a built in flash and therefore are not able to be used in a macro environment.